[Serusers] please help... sip parsing error

Can someone please help me figure out why I am getting this error from my SER: ERROR: t_newtran: EoH not parsed The message it is responding to is this: ACK sip:user@172.18.1.100:5060 SIP/2.0 Via: SIP/2.0/UDP 172.18.1.45:5060 From: "Cory Zue" <sip:czue@172.18.1.100>;tag=2005707378 To: <sip:user@172.18.1.100>;tag=1047340964 Call-ID: 1555446853(a)172.18.1.45 CSeq: 101 ACK User-Agent: Cory's VoIP UA Route: <sip:user@172.18.1.35:5060> Content-Length: 0 Every line in the message ends with a "\r\n". Any help with this problem, or where to look to get more output (see what line causes the error) would be greatly appreciated. thanks in advance, Cory